1. Field of Invention
The present invention relates generally to motor assemblies and, more specifically, to a method of biasing a worm shaft of a motor assembly.
2. Description of the Related Art
Conventional motor assemblies known in the art include an electric motor mounted to some type of housing in which a geartrain and an output shaft are supported. The geartrain typically converts rotational speed and torque from the electric motor and translates rotation to the output shaft. The geartrain often includes a worm drive with a worm shaft coupled to the electric motor, and a worm gear engaging the worm shaft, whereby the worm gear may be attached to other gears or linkages of the geartrain that are adapted to translate rotation to the output shaft.
Motor assemblies of the type described above are used in a wide variety of applications. As such, the geartrain of the motor assembly can be configured to convert rotation from the electric motor in a number of different ways depending on the application. Moreover, in certain applications, such as those requiring an oscillating rotational output shaft, reliable and consistent performance of motor assemblies is critical. Thus, alignment of the geartrain components is equally important. Specifically, any slack resulting from manufacturing and engagement tolerances of the various components must be eliminated or significantly minimized, as even a slight amount of slack can cause serious performance issues in operation. Further, slack causes backlash, slipping, and wear on the components of the geartrain. As wear increases, slack increases exponentially, which inevitably leads to catastrophic failure of one or more geartrain components. Typically, slack in the geartrain accumulates at the worm shaft and causes the worm shaft to move axially within the housing. Thus, efforts to reduce or eliminate slack known in the art tend to focus on preventing the worm shaft from slipping against the worm gear or moving axially within the housing. To that end, the worm shaft is typically biased during the process of manufacturing the motor assembly, so as to remove slack in the geartrain.
Each of the components of a motor assembly of the type described above must cooperate to effectively translate rotation from the electric motor to the output shaft. In addition, each of the components must be designed not only to facilitate improved performance and efficiency, but also so as to reduce the complexity of manufacturing the motor assembly and removing slack from the geartrain. While the motor assemblies known in the related art have generally performed well for their intended purpose, there remains a need in the art for a method of biasing motor assemblies that have superior operational characteristics and, at the same time, reduces the cost and complexity of biasing the motor assembly.